In some cases, a turbocharger is provided with a waste-gate valve to suppress an excessive increase in the boost pressure. The waste-gate valve adjusts the inflow amount of exhaust gas to an exhaust turbine by opening and closing a bypass passage that bypasses an exhaust turbine of a turbocharger.
A type of such waste-gate valve opens and closes the bypass passage by moving a valve body with an open-close lever, in case of which, for instance, the open-close lever and the valve body are coupled by inserting a valve shaft of the valve body into an insertion hole of the open-close lever, and providing a stopper (e.g. swaging part or washer) for the tip of the valve shaft. In this type of waste-gate valve, the valve body rotates about the axis of the valve shaft due to an influence from vibration of the engine or exhaust pulsation and makes slide-contact with the insertion hole of the open-close lever or the valve seat, and thus abrasion is likely to occur at the portion in contact with the valve body.
The waste-gate valve described in Patent Document 1 is provided with a groove having a rotation stopping surface in the insertion hole of the open-close lever (operation lever) to limit rotation of the valve body about the axis of the valve shaft described above, and a rotation-stopping washer having a side surface to contact the rotation stopping surface is engaged with the groove and, the washer is fixed to the valve shaft.